CHAPTER I 

 A GENERAL VIEW 



Vegetable forcing is an important branch of vegetable 

 gardening or olericulture. It relates to the growing of 

 vegetables to maturity or to edible size in greenhouses, 

 hotbeds, coldframes, or other special structures. The 

 cultural conditions are usually artificial throughout the 

 growing period, although there are exceptions, as when 

 lettuce is planted in frames during the spring season and 

 the glass dispensed with for a few weeks previous to the 

 harvesting of the crop. Of the various branches of oleri- 

 culture, vegetable forcing is the most intensive and the 

 most highly specialized. The cultural conditions must be 

 created and kept under absolute control, in order that the 

 best results may be realized. Because of this possibility, 

 vegetable forcing is often regarded as the most certain or 

 most reliable branch of vegetable gardening. 



The history of vegetable forcing in the United States 

 began with the use of hotbeds by the pioneer gardeners. 

 Hotbeds were employed mainly for the starting of the 

 early plants, although growers found it profitable to 

 mature some crops, especially lettuce and radishes, in 

 hotbeds heated by manure. Previous to 1880 very few 

 greenhouses were devoted to vegetable forcing, and their 

 use for that purpose at all was very infrequent until 1888. 

 The first houses were low and narrow mere toyhouses 

 as compared with our modern structures covering acres 

 of ground. Houses 11 feet wide and about 100 feet long 

 were common, and later some were built that measured 

 20 or 22 feet in width and more than 100 feet in length. 



Vegetable forcing, however, was not of great commer- 

 cial importance until after 1890, and the industry has 



